1. Field of the Invention
The present invention relates to golf balls. More particularly, the present invention relates to multi-piece golf balls having a center, a mid layer and a cover.
2. Description of the Related Art
Flight performances are important for golf balls. The flight distance correlates with the speed of the ball immediately after the impact. This speed correlates with the resilience performance. With respect to the resilience performance, a variety of proposals have been made.
Japanese Unexamined Patent Application Publication No. 2006-223874 (US 2005/176523) discloses a golf ball having a center, a first mid layer, a second mid layer and a cover. The resilience coefficient of a spherical body including the center and the first mid layer is greater than the resilience coefficient of the center. The resilience coefficient of a spherical body including the center, the first mid layer and the second mid layer is greater than the resilience coefficient of a spherical body including the center and the first mid layer. The resilience coefficient of the golf ball is greater than the resilience coefficient of a spherical body including the center, the first mid layer and the second mid layer.
Japanese Unexamined Patent Application Publication No. 2006-223875 (US 2006/189413) discloses a golf ball having a center, a first mid layer, a second mid layer and a cover. The resilience coefficient of a spherical body including the center, the first mid layer and the second mid layer is greater than the resilience coefficient of the golf ball. The resilience coefficient of a spherical body including the center and the first mid layer is greater than the resilience coefficient of a spherical body including the center, the first mid layer and the second mid layer. The resilience coefficient of the center is greater than the resilience coefficient of a spherical body including the center and the first mid layer.
Japanese Unexamined Patent Application Publication No. 2006-230661 discloses a golf ball suitable for golf players who hit with a low head speed. This golf ball has a core, a mid layer and a cover. In this golf ball, a highly resilient material is used for the mid layer.
The resilience coefficient correlates with the rigidity of the golf ball. Highly rigid golf balls generally have a great resilience coefficient. However, when such highly rigid golf balls are hit by golf players with less power, sufficient flight distance may not be attained because the golf ball is not appropriately deformed when the golf ball is hit by the golf players with less power, i.e., golf players who hit with a low head speed.
Golf players with less power desire for improvement of the flight performances of golf balls. An object of the present invention it to provide a golf ball that is excellent in the flight performance upon hitting with a low head speed.